celery/celery — pull request #836 by dmarkey (2012-07-03 23:03:36+00:00)
Title: When ACKS_LATE is enabled, make sure the message is ACK'd on a retry

It seems that when ACKS_LATE is enabled, retried tasks aren't ACK'd, this will hang a worker.. This patch ACKs retried tasks...

Dunno if 2.5-backport is being maintained however.. Same problem exists in master, will send pull request for it too..